That physique got him turned away when he tried to volunteer to fight the Soviets in the Winter War, but it didn’t put the Gestapo off him after Germany occupied Norway in 1940. He formed an informants’ network known as the Rinnanbanden which infiltrated the resistance movement and entrapped anti-occupation Norwegians — a “game in the negative sector,” as Rinnan described it.

The “game” got more than a thousand people arrested and something like 100 killed, including one of the more notorious episodes of the occupation, the Majavatn affair. (Norwegian link) It also eventually got Rinnan a German rank and the opportunity to kill some people personally.

Twelve people in all from the Rinnanbanden were sentenced to death after the war, counting Rinnan. Ten of those did indeed pay the penalty.